Immunostimulatory oligonucleotides

Abstract

Compositions and methods for stimulating toll-like receptor 9 (TLR9) are provided. More particularly, immunostimulatory oligonucleotides, methods of enhancing immunostimulatory properties of oligonucleotides, and methods of eliciting immune responses are disclosed herein.

What is claimed: 
     
         1 . An immunostimulatory oligonucleotide comprising at least one CpG motif and a 3′ cholesteryl moiety. 
     
     
         2 . The immunostimulatory oligonucleotide of  claim 1  comprising phosphodiester linkages or phosphorothioate linkages between nucleotides of the immunostimulatory oligonucleotide. 
     
     
         3 . The immunostimulatory oligonucleotide of  claim 1 , wherein the cholesteryl moiety is covalently attached to the 3′-terminal nucleotide of the immunostimulatory oligonucleotide via a linker. 
     
     
         4 . The immunostimulatory oligonucleotide of  claim 1 , further comprising a 3′ terminal sequence comprising a plurality of thymine nucleotides. 
     
     
         5 . The immunostimulatory oligonucleotide of  claim 4 , wherein the plurality of thymine nucleotides comprises consecutive thymine nucleotides. 
     
     
         6 . The immunostimulatory oligonucleotide of  claim 4 , wherein the plurality of thymine nucleotides comprises between 4 and 6 consecutive thymine nucleotides. 
     
     
         7 . The immunostimulatory oligonucleotide of  claim 1 , wherein the 3′ terminal sequence is TTTT. 
     
     
         8 . The immunostimulatory oligonucleotide of  claim 1 , wherein the 3′ terminal sequence of the immunostimulatory oligonucleotide comprises a plurality of guanine nucleotides. 
     
     
         9 . The immunostimulatory oligonucleotide of  claim 8 , wherein the plurality of guanine nucleotides comprises consecutive guanine nucleotides. 
     
     
         10 . The immunostimulatory oligonucleotide of  claim 8 , wherein the 3′ terminal sequence is GGGGG. 
     
     
         11 . The immunostimulatory oligonucleotide of  claim 1 , wherein the immunostimulatory oligonucleotide comprises (TCG) n , where n is between 3 and 10. 
     
     
         12 . The immunostimulatory oligonucleotide of  claim 4 , wherein the linker comprises a carbon chain. 
     
     
         13 . The immunostimulatory oligonucleotide of  claim 12 , wherein the carbon chain comprises between 3 and 12 carbon atoms. 
     
     
         14 . The immunostimulatory oligonucleotide of  claim 3 , wherein the linker comprises a hexanediol. 
     
     
         15 . The immunostimulatory oligonucleotide of  claim 1 , wherein the oligonucleotide further comprises a cholesteryl-linker moiety having the following structure: 
       
         
           
           
               
               
           
         
       
     
     
         16 . The immunostimulatory oligonucleotide of  claim 3 , wherein the linker comprises a repeated chemical unit, optionally repeated between 2 and 12 times. 
     
     
         17 . The immunostimulatory oligonucleotide of  claim 16 , wherein the repeated chemical unit is an ethylene glycol or hexaethyelene glycol. 
     
     
         18 . The immunostimulatory oligonucleotide of  claim 1 , wherein the cholesteryl moiety is covalently bound to the linker to form a cholesteryl-linker moiety having the following structure: 
       
         
           
           
               
               
           
         
       
     
     
         19 . An immunostimulatory composition comprising the immunostimulatory oligonucleotide  claim 1 . 
     
     
         20 . A method of eliciting a TLR9-mediated immune response in a subject comprising administering to the subject the immunostimulatory oligonucleotide of  claim 1 .